Apparatus for heating



MAY 21', 1940- J. c. wooDsoN 2,201,386

APPARATUS FOR HEATING Filed Nov. l5, 1938 2 Sheets-Sheet 2 lNvEN-roR dames C. Woodson g, Mx/2mdk 50 heat-resistant alloy.

Patented May 21, 1940 APPARATUSv FOR HEATING James C. Woodson, Cleveland, Ohio, assignor to Lee Wilson Sales Corporation, Cleveland, Ohio,

a corporation of Ohio Application November. 15, 1938, Serial No. 240,498'

4, Claims.

This invention relates in general to heating, and in particular to a heating element particularly adapted for installation in furnaces, al-

though it may b e utilized in other applications.'

y Various types of indirect heaters for furnaces and the like have been proposed heretofore. It is an `object of this invention to improve generally upon such devices and, in particular, -to provide a radiant heating element adapted to be heated by the combustion of fuel, which is simple,` sturdy, and relatively inexpensive in construction and eiiicient in operation. In a preferred form, the heating element of my invention comprises a radiant tube of generally flattened character havl5 ing a baflle extending thereinto dividing the tube into a pair of passages. Inlet and outlet ports are provided adjacent one end of the tube and a burner is provided for the inlet port. The burner supplies a combustible mixture of fuel and air to one of the passages along the tube for combustion therein to heat the latter to radiant temperature. After passing along the length of the tube in one direction, the gases sweep around the end of the baie and return the full length of the tube in the other direction. Conveniently, the baiiie may be in the form of a pipe for supplying secondary air to the combustion products4 at a point spaced from the burner.

The following detailed description of the invention refers to the accompanying drawings illustrating the aforementioned embodiment as applied to a typical installation. In the drawings: Fig. l is a longitudinal central section through a furnace having heating elements of my Invention mounted therein;

Fig. 2 is a transverse sectional view taken along line II-II of Fig. 1; line I--I of Fig. 2 illustrates the plane on which the section of Fig; 1 is taken; Fig- 3 is a sectionaLview taken along the line III- III of Fig. 2 with parts omitted; and

Fig. 4 is a vtransverse sectional view taken along the plane of line IV-IV of Fig. 3.

Referring now inV detail to the drawings and. for the present, to Figs. 3 and 4 particularly, a heating element embodying my invention, indicated generally at lil, comprises artube II which, as shown, is preferably corrugated to increase its rigidity. The tube may be of relatively light gauge metal and is preferably composed of Va As shown in Fig. 4, the widtho the tube I0 is several times its thickness, the section of the tube being of .oval shape.

A casting I2 is'welded to one end of the tube and is provided with an inlet port I3 andan ex- M haust port Ill. The casting I2 also has a port I5 for the reception of a baille pipe I6 extending into one end of the tube I I and terminating just short of the other end. As shown in Fig. 4, the pipe I6 serves as a baille dividing the tube II into lower and .upper chambers I'I and I8. While the pipe 5 I6 is spaced slightly from the side walls of the tube II, permitting some -by-passing of combustion gases from the lower passage I1 to the upper passage I8, the major volume of the gases will be compelled to travel the length of the passage I1 10 before entering the passage I8.

A return bend casting orA closure I9 is welded into the end of the tube I I opposite that to which the casting I2 is secured.

Considering now more particularly Figs. 1 and 15 2, illustrating a typical installation of heating elements according to my invention. an enameling furnace or the like 20 has side walls. 2l, a hearth 22 and a roof 23 assembled within a structural framework including buckstays 24. One end wall 20 25 of the furnace has a charging opening 28 therein adapted to be opened and closed by a door (not shown).

Heating elements I0 -are mounted on the side walls 2| and the hearth 22, being supported there- 25 on by brackets 21. 'Ihe inlet and exhaust ports: of the heating elements are disposed adjacent the end wall 28 of the furnace. inlet and exhaust pipes 29 and'30 extending from said ports and through the end wall 28,. AV burner 3i is posi- 30 tioned in each of the inlet pipes 29 and is connected by piping, as shown in Fig. 1, to a suitable source of fuel or combustible mixture of fuel and air (not shown). The baille pipes I8 of all the heating elements are connected to an air supply 35 header 32 which-is in communication with asupply of air under low pressure such as a blower (no shown). l l

The exhaust pipes 30, leading from all the heating elements, are in communication with an 40 exhaust duct 33 which may be connected to astack if natural draft is relied on,. or to a suitable exhaust fan or ejector if forced draft is desired.

It will be apparent from the foregoing description that the burners 3I supply a combustible 45 mixture to the passages I1 of the heating elements I il for combustion therein `and that the resulting products of combustion/flow for the most part alongl the length of the passages I1, around the end of the baiile pipes and return 5o along the passages I8 to the exhaust pipes 30 and duct 33. As already stated, some Y small portion of the gases is by-passed from the passages I1 to the passages I8 around the baille pipes I6. The tubes .II of the heating elements The structure of the vheating elements I0 is quite simple and relatively inexpensive.

At the same time, a high degree'of thermal efliciency may be obtained therewith because of the long path of travel provided for the major part of the combustion gases in the tubes I l. `The introduction of secondary air at points remote from the burners, furthermore, also increases the eiiciency of combustion. f

, `While I have illustrated and described herein but one form of heatingveleme'nt and but one typical installation thereof, it-will be understood that changes in the construction disclosed and the manner of utilizing it may be madev without departing from the spirit of the invention or the scope of the appended claims.

I claim:

l. A radiant heating element comprising an elongated sheet metal tube, one dimension of the transverse section of the tube being several times A11 joints in the4 ascisse the other dimension, a cap at one end of said tube, a closure at the other end of the tube having inlet and outlet ports on opposite sides of the central plane therethrough and a substan tially central port, a pipe extending through said vcentral port, terminating short of said cap and serving as a secondary air conduit, said pipe being of such size relative to said other dimension as to constitute a baille dening entering and return passages for combustion gases and substantially restricting flow of such gases from the entering passage to the return passage except by a path laround the end of said pipe.

2. A radiant heating element as dened by claiml characterized by said cap and closure `having a wall thickness greater than that of said tube.

3. A radiant heating element as defined by claim 1 characterized by said tube having a secr `'tion of substantially oval shape.

4. A radiant heating element as defined by claim 1 characterizedby said cap and closure ybeing castings having a wall thickness greater than said tube.

`JAMES C. WOODSON.y 

